Unloader



sept. 15, 1931. G. HAZARD' 1,823,398

UNLOADER Filed Dec. 22, 7.926

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Patented sept. 1s, 1931 UNITED STATE-s 'PATENT omer.

GEORGE EDGAR. HAZARD, or EocEEsfrEa, NEW Yonx. AssrGNon 'ro KELLoGGMANU- rac'rUnrNG co., or nocnEs'rEn, NEW vom:

i UNLoADEn Application filed December 22, 1926. Serial No. 156,421.

This invention relates to improvements in unloaders being directed moreparticularly to an automatically o erated unloading device orcontrolling t e pressure in a storage tank'or the like which tank isbeing sup' plied Vwith compressed air from the compressor.

The primary object of the present invention is the provision of anautomatically operated unloadin unit of novel construction forautomatical y controlling the air presure in a storage tank or the like.

A" still further object of the invention is the provision of anautomatically operated lsunloading device for use with a compressor orthe like for automatically opening and holding open the air intake valveof a "compressor or the like at a predetermined time. V zo A stillfurther object of the invention is the provision of a device of thecharacter .described which is chea and simple to manufacture and highlyetliient in operation.

@ther novel features of construction and improved results of theinvention will appear from the following' description and the-accompanying drawings.

In the drawings: Figure 1 is a vertical sectional through the unloader.

Figure 2 is an end view in side elevation of they device.

Figure 3 is an enlarged view of the bleeder screw. f

The present invention is an automatically operated unloading devicewhich has been developed and is primarily used with an air compressorwhich is in continuous operation. The purpose of the device is toprotect the compressor and storage tank so as to'prevent view thebuilding up of an excessive air pressure whichv might result in theblowing up of the storage tank. The further and second purpose of theinvention is to assurethat the compressor will at all times begin itswork against zero or atmospheric pressure.

' Describing the invention' in detail it will be seen that the unloadingdevice is providved with an linlet opening 5 which opening is adaptedyto communicate with an air pipe lmally closed by a valve 11 which is ofa U- (not shown) running to a storage tank (not shown). From this itwill be seen that `the unloader is at all times in constantcommunication with the air storage tank. The air inlet opening 5 at itsinner side is in communication with two ports or channels 6 and 7 Thevchannel or port 6 terminates in an enlarged circular valve chamber 8which chamber has an open outer end and is provided with acircumferential seat 9 in which is positioned a closure 10. Thel o uterwall of the chamber 8 is externally threadv ed as at 23 to receive andsupport a hollow pl l2.

ounted within the hollow plug and adapted for reciprocation therein i isa plunger 13 which plunger is provided internally with a ball 14 uponwhich is superimposed a coil spring 15, the outer endof which earsagainst adJusting screw or plug 16, which is internally threaded in theouter end of the plug 12 as at 17. .The adjusting screw 16 is providedon its outer face Vwith a slot 18 whereby the screw may be readilyturned through the medium of a screw driver or other suitable tool. Alocking nut 19 is provided or locking the said screw in its adjustedposition. The unloader is provided centrally with an air receivingplunger chamber 20, the in- 80 let channel or opening of which isdesignated at 21, The inlet channel 21 extends into the chamber 8 in theform of a pipe-like member 22. The inlet end of the channel 21 isnorshape in cross section and is of a width'approximately the same asthe widthof the chamber 8 whereby the side walls of the chamber act as aguide for the valve in its movement. A coil spring 24k surrounds thepipe-like portion of the inlet 22 and exerts a normal outward pressureupon the valve 11. The central chamber 20'has an open lower end which isin' communication with the circular chamber 25, the lower end of thechambei-.being externally screw threaded as at 26 and it is bymeans ofthese screw threads that the unloader is fastened in a compressor clinder head (not shown) above the inlet v ve 100 thereof (not shown).The lower end of the chamber 25 is closed by a plug 27 which isexternally screw threaded therein as at 28.

This plug is held in locked position by means of a set screw 29.

Mounted within the chamber and adapted for reciprocation therein is adisc `wh1ch floats freely on a carrier 31 which carrier is supportedupon a plunger rod 32 which isv of a length toextend well "beyond theclosing plug 27 and into the compressor cylinder sleeve 37 at its otherend, thus exerting a normal upward pressure upon the'disc carrier Y anddisc and holding the disc in closed position against the lower 4open endof thecentral chamber 20. A Vlock nut 38 is provided for locking theunloader inthe compressor cylinder head opening. v

The channel or port 7 heretofore referred to has its lower end normallyclosed by a hand operated valve 39. The purpose of this hand operatedvalve is to enable the compressor to be started by hand if there is anypressure' i in the storage tank, as otherwise the air in the cylinder ofthe compressor on top of the piston, if it were not relieved, would putan excessive load on the engine or motor driving the compressor andwould cause diiculty there or would have a tendency to throw olf thedriving belt or burn it. By means of this hand operated screw thecompressor may be started when the conditions 4are such as has been justabove described. t

For the purpose of preventing dirt entering the device through thepassage 5 and interfering with its operation, a suitable air strainer orfilter 41 usually composed of felt, isplaced in the passage 5, and thisfilter is held in position and prevented from clogging up the passages 6and 7 by means of a suitable screen 41 placed immediately below saidfilter.'

sleeve 37 of the disc carrier and that the plunger is provided with ayreduced upper end 42 that enters the disc carrier so as to cause theplunger and gether at all times.v

, Attention is directed Ito a bleeder or regulating screw 44 whichpasses through the side of the housing 1 and has its inner .ta-l

pered end 45 adapted to enter an opening 46 formed in the chamber 20.screw has one side flattened throughoutits length as shown at 47'whereby an air passage is formed carrier to move/tobetween the screwand the wall of its opening.

.A lock nut 48 serves to lock the bleeder screw in its adjustedposition. The object of providing this bleeder screw or member is causea difference between the pressure 1n the chamber 20 and the pressurethat is in seated against a cone-shaped seat 30. i The object of this isthat when the disc 30 is unseated, then a larger surface of exposure iscreated which causes it to act in a snappy and powerful manner and causethe rod 32 to quickly act upon the part which it engages.

The cover 0r top 10 of the 4chamber 8 is held against its seat by'meansof a suitable metallic ring 43 which is pressed downward by the member12 thatis screwed in position. In this manner the top or cover 10 isheld to its seat and it has onlyl a buckling movement back and forth tocause the valve 11 to be seated and unseated on the pipe-like member 22.

I am aware that it is not new `to utilize a thin disc or diaphragmacting as a valve adapted to act directly on the outlet member 22 whichhas a tapered seat for it. In practice however it is Afound that thisconstruction is not durable because the valve seat also aware that aconical valve has heretofore been used that seats in the conical openingof the member 22. Such a construction however has been found impracticalin devices of the character here'described because it is very diiiicultto properly-seat the conical valve to make a closure. For this primaryreason conical valves are considered as impractical in such aconstruction. There- Vfore I have devised the combination of a ilexibleclosure 10 which serves to close the end of the chamber 8 and I placethe U-shaped valve 11 composed of the relatively thick non-iexiblematerial located betweenand its o osite sides in en a me t 'th th tAttention isy directed to the fact that thev pp g ge n W1 e a upper endof the plunger 32 is within the pered seat of the outlet member 22 andthe flexible plate or diaphragm 10. I have also :found such a valveneedsmeans for accurately guiding and supporting this valve and Iaccomplish it by making the valve U- shaped in cross section so that itlits properly against the walls of the chamber 8 and thereby guides thisheavier metal valve and also Serves to cause the plate valve toaccurately fit against the tapered'seat of the member 22 therebyinsuring at all times an accurate and tightgitting of the parts. It willthus be seenthat this construction avoids all of the objections tostructures that'have been before used in this relation.

Operation The parts having the adjustments here shown, operate asfollows: The pressure being built up` in the pressure tank, flowsthrough the passageway 5, the strainer 41 and the passage 6 and thepressure then acts againstthe underside of the U-shaped valve 23.When'the pressure in the storage tank has reached its limit, thelpressure Ain .the chamber 8 lifts thevalve 11, when the pressure willi'low through the pipe-shaped member 2l into the chamber20. Apart ofthis pressureis allowed to escape by means of the bleeder screwv 44. Thepressure in the chamber acting on the disc 30, causes it to move fromits seat which being cone-shaped, the diameter of the disc is increased,causing it to act in a snappy manner and with power on the rod 32. Allthe time that the pressure tank is unloading, air is escaping by thisbleeder screw 44, thereby causing a differential pressure between thepressure of the storage tank andv the pressure of the chamber 20,whereby the pressure in the chamber 2O is less than the pressure'in thestorage tank, causing the disc 30 to return upward to the position shownin the drawings. When the disc 30 is moved downward, it iinally reachesthe member 34 against which the valve seats.

While I have described my construction in 4 Having thus described myinvention, what I desire to claim and secure by Letters Pat- A ent is:

1. An unloader adapted for use with air compressors or the like,comprising a casting having therein an air inlet in communication with achamber, an air outlet from said chamber to a second chamber, a valvearranged in said first chamber and adapted to normally close the outletpressure, a dlsc positioned below said second chamber, a carrier forsaid disc, a guide for said carrier, a plunger havmg connection withsaid carrier, and resilient adjustable meansfor normally holding thevalve in a closed position in respect to the outlet opening from thefirst chamber, whereond chamber, an inlet adapted to receive air'pressure in communications-with said valve chamber, commumcation betweensa1d valve 05 chamber and sald second chamber, a valve detail, I do notdesire to limit myself since by a predetermined amount of air is rluired in said valve chamber adapted to normally close communicationbetween said chambers, v

a housing having communication with said second chamber, a disc mountedin said housing and adapted for reciprocation therein, a carrier forsaid disc and a guide for said carrier, a plunger having connection withsaid carrier and adapted for engagement with the inlet valve ofthecompressor, and ad'ustable resilient means for normally holdmg the valvein the valve chamber in a closed position, whereby a predeterminedamount of air is required to unseat said valve.

3. -An unloader adapted for use with a compressor or the like, comrising a castin having therein a valve cham er and a secon chamber, anair inlet in communication with a pressure supply at one `end and saidvalve chamber at its other end, an air passage providinv communicationbetween the valve 'chamber and the second chamber, said passage havingan extending end into the valve chamber, a valve in said valve chambernormally seated upon said extending end to close the same, said valvebeing U-shape in cross section and guided throughout its movement by theside walls of the valve chamber, a housing mounted below the secondchamber and having therein a seat, a plunger in said housing, a disccarrier mounted upon said plunger,

a disc mounted upon said carrier, a ide for said disc carrier, meanstonormally old said plunger, disc carrier and disc in elevated positions,and adjustable resilient means to normally hold the aforesaid valve in aclosed position upon its seat, whereby mined amount of air pressure 1srequired to unseat said valve to permit the passa e of air to the secondchamber for operating t e members in said housing.

4. An unloader comprising a housing havin'g a valve chamber and an' airreceiving passageway communicating therewith, said chamber havingprojecting withln said chamber and its outer end in communication with asecond chamber, a flexible member closing the said valve chamber, aU-shaped valve of heavier metal than the said flexible member for thepurpose scribed located between said flexible member and the outer endof said projecting outlet and adapted to seat on the said projectingoutlet, means for constantly exerting ressure on said valve to cause itto norma y be seated, and a Iplunger mechanism in communication wit thesaid secon'd chamber.

5. An unloader of the type described comprising a housing having a valvechamber and an air receiving passageway communicating with said chamber,an outwardly projecting outlet havinga tapered outer end communicatingwith the said chamber and its inner end communicating with a second,chamber, a flexible member closing the outer end of said rst mentionedchamber, a

a predeterf an air outlet with one end v 4 1,sna,ses

v/ U-sha d valve of relatively heavier material than e said ilexiblemember located between the said flexible member and said outwardlypro'lecting outlet and in engagement there- 5 wit the inner side of thesaid valve be` adapted to seat on the tapered projecting en of theoutlet, means for ressin the sald exible member and there y sai valvein. engagement with its lsaid seat, said second l0 chamber having oneend open, a cylinder in communication with'the said chamber and ofconsiderably larger diameter than the said chamber, said open end havingits outer end ta ered outwardly, a plunger in the said cyl- 15 in er, adisc carried b the said plunger and fitting within the said, cylinderwhereby an increased pressure on the disc is effected when it moves offits seat adjacent said second chamber. v

2 6. A compressor unloader comprising a housing provided with a chamberhaving an air inlet, said chamber having a passageway v y establishingcommunication between it and a second chamber, a valve controlling saidlast 25 mentioned passageway, a plunger mechanism in communication withthe second chamber, a constantly open bleeder passageway incommunication with the second chamber for the purpose of establishingdifferential pres- 30 sures between the two chambers, and a manuf allyoperated valve for said bleeder passai:-

way adapted to establish communication `tween the air inlet and thesecond chamber r by manual operation to relieve the pressure l5 in thecompressor when the same is started,

" for the purpose described. In testimony whereof I hereunto aix mysignature.

" GEORGE EDGAR HAZARD.

